One important measurement associated with performance testing of Layer 4-7 devices relates to the determination of the number of concurrent transmission control protocol (TCP) connections a device under test (DUT) can simultaneously keep active. Specifically, the ability to merely maintain a large number of connections in an open state may not be sufficient for some test purposes. Rather, it is important to ensure that each tested connection is actively communicating packet traffic on a relatively frequent basis. Notably, if an open TCP connection does not transport any traffic for an extended period (i.e., even if the connection is not expressly closed), a network device (or a DUT) may interpret the non-active TCP connection as being down and subsequently close the connection in order to free up the associated memory resources for other requirements.
Although a test system may be readily configured to open the largest number of possible connections and allow a tested device to freely conduct packet transactions without any control, employing such an approach is not without problems. Specifically, if the connections are configured to conduct the transactions independently, then the connections may be closed independently as well. Consequently, the total number of opened connections may fall to significantly low numbers during a testing period. Likewise, an opened TCP connection that does not exchange traffic consumes less memory than a TCP connection that is actively communicating packet traffic. Thus, if all the connections are allowed to exchange traffic without any control, the total memory consumption of the emulation system can rapidly approach and reach its maximum level.
Accordingly, there exists a need for methods, systems, and computer readable media for sustaining active control over concurrent session connections.